Attorney General's legal advice

It comes after Attorney General Geoffrey Cox told MPs the legal risk of being tied to the EU after Brexit "remains unchanged".

He added that the new assurances secured by the PM did "reduce the risk that the United Kingdom could be indefinitely and involuntarily detained" in the Irish backstop if talks on the two sides future relationship broke down due to "bad faith" by the EU.

He defined "bad faith" as a "pattern of refusing to accept reasonable proposals" on the Irish backstop.

But he said the question of whether a satisfactory post-Brexit deal on a permanent trading relationship can be reached remained "a political judgment" - and he said MPs should back the PM's deal.

In his advice, Mr Cox said "the legal risk remains unchanged" that if a post-Brexit trade agreement can not be reached due to "intractable differences", the UK would have "no internationally lawful means" of leaving the backstop without EU agreement.

More reaction from MPs

Image copyrightHOCImage caption
Ian Blackford accused the PM of 'laughing' during his speech

Mrs May earlier addressed a meeting of Conservative MPs, in an effort to change the minds of those opposed to her deal.

Conservative MPs leaving the meeting suggested half of those who voted against the deal last time will switch to support it later, said BBC's Chief Political Correspondent Vicky Young.

Work and Pensions Secretary Amber Rudd said she believed the prime minister's deal would go through "otherwise instability will follow which would be so unwelcome".

But Brexit-backing former foreign secretary Boris Johnson told MPs: "I am afraid this deal has now reached the end of the road and if it is rejected tonight I hope that it will be put to bed."

He said the only option to preserve the UK's "self-respect" was to leave on 29 March, without Mrs May's agreement, and then negotiate a free trade deal.

But the EU's chief Brexit negotiator Michel Barnier tweeted that the idea of a "transition period" without the withdrawal agreement agreed with Mrs May was a "dangerous illusion" with no legal basis.

Brexiteer Conservative MP Andrea Jenkyns said the UK should leave the EU "without a bad deal", adding that the country needed to look "beyond the borders of the EU".

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Media captionSnap general election on the cards, says Conservative MP

Liberal Democrat leader Sir Vince Cable told MPs Brexit will "make this country poorer, weaker and less secure" and called for people to have the final say in another referendum.

And leading Tory Remainer Dominic Grieve warned "we are about to do a serious and historic mistake", describing Brexit as "self-mutilation".

He earned a rebuke from Speaker John Bercow for accusing Mrs May of "sitting there laughing" while he was "talking about the rights that will be taken away from our young people" by Brexit.

What was agreed with the EU?

Theresa May flew to the European Parliament with Brexit Secretary Steve Barclay on Monday for last-minute talks with Mr Juncker and EU chief Brexit negotiator Michel Barnier. She returned with three documents:

A "joint legally binding instrument" on the withdrawal agreement which the UK could use to start a "formal dispute" against the EU if it tried to keep the UK tied into the backstop indefinitely.

A "unilateral declaration" stating there is nothing to stop the UK from leaving the backstop if discussions on a future relationship with the EU break down and there is no prospect of an agreement.

Many MPs fear the backstop, initially agreed by the UK government in December 2017, would keep the country in a customs arrangement with the EU indefinitely.

The PM has claimed the new documents addresses this issue and urged MPs to back the "improved deal".

The EU warns 'this is it'

Image copyrightReutersImage caption
Theresa May and Jean-Claude Juncker gave a joint press conference after late night talks in Strasbourg

The UK is set to leave the EU on 29 March 2019 after voting to leave by nearly 52% to 48% - 17.4m votes to 16.1m - in 2016.

European Commission President Jean-Claude Juncker has warned MPs they would be putting everything at risk if they voted down the deal.

"In politics sometimes you get a second chance," he said. "It is what we do with that second chance that counts. There will be no third chance."

The Irish Prime Minister Leo Varadkar said the new agreements showed both sides' "good faith" - although he made clear they did "not undermine" the principle of the backstop or how it might come into force.

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What could happen this week?

Theresa May's deal to face a "meaningful vote" in Parliament later on Tuesday

If it's rejected, a further vote has been promised for Wednesday on whether the UK should leave without a deal

If that no-deal option is rejected, MPs could get a vote on Thursday on whether to request a delay to Brexit from the EU.